in java/org/apache/el/util/ReflectionUtil.java [135:321]
public static Method getMethod(EvaluationContext ctx, Object base, Object property, Class<?>[] paramTypes,
Object[] paramValues) throws MethodNotFoundException {
if (base == null || property == null) {
throw new MethodNotFoundException(
MessageFactory.get("error.method.notfound", base, property, paramString(paramTypes)));
}
String methodName = (property instanceof String) ? (String) property : property.toString();
int paramCount;
if (paramTypes == null) {
paramCount = 0;
} else {
paramCount = paramTypes.length;
}
Class<?> clazz = base.getClass();
// Fast path: when no arguments exist, there can only be one matching method and no need for coercion.
if (paramCount == 0) {
try {
Method method = clazz.getMethod(methodName, paramTypes);
return getMethod(clazz, base, method);
} catch (NoSuchMethodException | SecurityException e) {
// Fall through to broader, slower logic
}
}
Method[] methods = clazz.getMethods();
Map<Method,MatchResult> candidates = new HashMap<>();
for (Method m : methods) {
if (!m.getName().equals(methodName)) {
// Method name doesn't match
continue;
}
Class<?>[] mParamTypes = m.getParameterTypes();
int mParamCount = mParamTypes.length;
// Check the number of parameters
// Multiple tests to improve readability
if (!m.isVarArgs() && paramCount != mParamCount) {
// Method has wrong number of parameters
continue;
}
if (m.isVarArgs() && paramCount < mParamCount - 1) {
// Method has wrong number of parameters
continue;
}
if (m.isVarArgs() && paramCount == mParamCount && paramValues != null && paramValues.length > paramCount &&
!paramTypes[mParamCount - 1].isArray()) {
// Method arguments don't match
continue;
}
if (m.isVarArgs() && paramCount > mParamCount && paramValues != null && paramValues.length != paramCount) {
// Might match a different varargs method
continue;
}
if (!m.isVarArgs() && paramValues != null && paramCount != paramValues.length) {
// Might match a different varargs method
continue;
}
// Check the parameters match
int exactMatch = 0;
int assignableMatch = 0;
int coercibleMatch = 0;
int varArgsMatch = 0;
boolean noMatch = false;
for (int i = 0; i < mParamCount; i++) {
// Can't be null
if (m.isVarArgs() && i == (mParamCount - 1)) {
if (i == paramCount || (paramValues != null && paramValues.length == i)) {
// Var args defined but nothing is passed as varargs
// Use MAX_VALUE so this matches only if nothing else does
varArgsMatch = Integer.MAX_VALUE;
break;
}
Class<?> varType = mParamTypes[i].getComponentType();
for (int j = i; j < paramCount; j++) {
if (isAssignableFrom(paramTypes[j], varType)) {
assignableMatch++;
varArgsMatch++;
} else {
if (paramValues == null) {
noMatch = true;
break;
} else {
if (isCoercibleFrom(ctx, paramValues[j], varType)) {
coercibleMatch++;
varArgsMatch++;
} else {
noMatch = true;
break;
}
}
}
// Don't treat a varArgs match as an exact match, it can
// lead to a varArgs method matching when the result
// should be ambiguous
}
} else {
if (mParamTypes[i].equals(paramTypes[i])) {
exactMatch++;
} else if (paramTypes[i] != null && isAssignableFrom(paramTypes[i], mParamTypes[i])) {
assignableMatch++;
} else {
if (paramValues == null) {
noMatch = true;
break;
} else {
if (isCoercibleFrom(ctx, paramValues[i], mParamTypes[i])) {
coercibleMatch++;
} else {
noMatch = true;
break;
}
}
}
}
}
if (noMatch) {
continue;
}
// If a method is found where every parameter matches exactly,
// and no vars args are present, return it
if (exactMatch == paramCount && varArgsMatch == 0) {
Method result = getMethod(clazz, base, m);
if (result == null) {
throw new MethodNotFoundException(
MessageFactory.get("error.method.notfound", base, property, paramString(paramTypes)));
}
return result;
}
candidates.put(m, new MatchResult(m.isVarArgs(), exactMatch, assignableMatch, coercibleMatch, varArgsMatch,
m.isBridge()));
}
// Look for the method that has the highest number of parameters where
// the type matches exactly
MatchResult bestMatch = new MatchResult(true, 0, 0, 0, 0, true);
Method match = null;
boolean multiple = false;
for (Map.Entry<Method,MatchResult> entry : candidates.entrySet()) {
int cmp = entry.getValue().compareTo(bestMatch);
if (cmp > 0 || match == null) {
bestMatch = entry.getValue();
match = entry.getKey();
multiple = false;
} else if (cmp == 0) {
multiple = true;
}
}
if (multiple) {
if (bestMatch.exactCount() == paramCount - 1) {
// Only one parameter is not an exact match - try using the
// super class
match = resolveAmbiguousMethod(candidates.keySet(), paramTypes);
} else {
match = null;
}
if (match == null) {
// If multiple methods have the same matching number of parameters
// the match is ambiguous so throw an exception
throw new MethodNotFoundException(
MessageFactory.get("error.method.ambiguous", base, property, paramString(paramTypes)));
}
}
// Handle case where no match at all was found
if (match == null) {
throw new MethodNotFoundException(
MessageFactory.get("error.method.notfound", base, property, paramString(paramTypes)));
}
Method result = getMethod(clazz, base, match);
if (result == null) {
throw new MethodNotFoundException(
MessageFactory.get("error.method.notfound", base, property, paramString(paramTypes)));
}
return result;
}